Blower



Patented Feb. 5, 1946 UNITED STATES; PATENT oFFICE Claims.

This invention relates to a blowerparticularly of that type which will have a high volume discharge up to several inches of water pressure.

A primary advantage of the invention is that by reason of the particular construction, there is simultaneously secured a quiet inlet condition; a high pressure building mid-section of the blades; and a high volume discharge. Further, by reason of the construction of the blades and their mounting a full loading of the blades is secured entirely back to the inner ends thereof. By using a larger inlet opening ring than the diameter of the blade inlet edges, leaving uncovered parts of the ends of the blades, an improvement in inlet condition is secured. Also there is the advantage obtained by extension of the blade mounting back plate and the outer blade engaging ring to form radially extending flanges from the blades whereby a. better deliveryof air against pressure promotes increased efficiency of the rotor.

Other advantages of the invention are gained from the construction to permit use of blades of much thinner steel than is found in the heretofore used rotors, all without loss of mechanical strength and air delivery efficiency; rigid mounting of the blades even in long units without requiring use of bracing rods; in general the use of like stampings throughout; and such other advantages as will become apparent to those skilled in the art in the following description of one particular form of the invention as illustrated in the accompanying drawings, in which Fig. 1 is a view in side elevation of a structure embodying the invention;

Fig. 2, a view in back side elevation of a blade on an enlarged scale;

Fig. 3, a view in leading edge elevation of the blade on an enlarged scale;

Fig. 4, a view in elevation of the inlet end of the blade on an enlarged scale;

Fig. 5, a view in rear end elevation of the blade on an enlarged scale; and

Fig. 6, a view in discharge end elevation and partial section of the blower.

Like characters indicate like parts throughout the several views in the drawings.

In the present showing of the invention a double axial inlet type of blower is employed. A scroll I0 is formed out of suitable material, such as sheet metal to have a discharge .end opening I I and circular inlet openings l2 and IS on the sides. These openings I2 and I3 appear between curved-in side wall flanges of the scroll III.

Suitably mounted to rotate in bearings (not shown) axially of the openings I2 and I3 is a rotor shaft I4. A pair of generally frusto-conical plates I5 and I6 are centrally disposed between the inner ends of the flanges forming the openings I2 and I3, in fixed engagement along and with the shaft l4. These plates I5 and I6 are mounted as indicated in Fig. 6 to have their peripheral base portions in abutment and preferably secured one to the other by any suitable means, such as welding. The outer peripheral portions of the plates I5 and I6 present planar surfaces perpendicular to the axis of the shaft I4. Around these peripheral portion in closely spaced relation are mounted and secured thereto a plurality of blades I'I. These blades extend from the respective plates I5 and I6 in general parallel alignment with shaft I4 outwardly toward the respective openings I2 and I3.

Referring particularly to Figs. 2 and 5, each of these blades I! has an inner end mounting flange I 8 formed to turn from the rear or trailing side of the blade and to bear against the respective plates I5 and I6 as the case may be. In the present form of the invention this flange I8 is spot welded to the plates I5 and I6 in each instance. The blade is generally arcuate in shape but has portions thereof of difierent radii as opposed to the heretofore generally employed constant radius of curvature blade.

The blade II has a straight inner edge A parallel to the axis of the shaft I4. From this edge A the blade curves backwardly with a 1% unit radius, Fig. 5, to have its leading face merge into the flatter curved zone of 1% unit radius, which flatter area extends over a major part of the leading side of the blade. From this flatter area, the blade curves around more sharply by a unit radius to the outer edge B. These dimensions are maintained substantially throughout a wide range of diameters of rotors. In the present showing of the invention a blade having the configuration described in accordance with the dimensions named is used in a 12 inch diameter rotor. Lengths of the blades I! will vary depending upon the volume of discharge desired.

The inlet end of the blade, Fig. 4, is provided with an intur'ned flange I9, that is turned in the opposite direction from the inner mounting flange I8. This flange I9 is cut away as indicated in Fig. 4 to have a curvature of 1 unit radius from the edge A back to a point C, from which the flange I9 extends in substantially full width around to the outer edge B. The dimensions indicated in Figs. 4 and 5 are maintained rather closely to give the desired blower blade eificiency. Preferably the inner and outer edges of the blade I! are rounded to be free of any burrs or roughness. In the present form of the invention, the blades IT, by reason of their shape and contour can be made of stainless steel down to .010 inch in thickness. The blades I! are located around the respective plates I5 and I6 to have their inner edges A; unit back of a radial line across the outer edge, Fig; 1.

After the desired number of blades I! are mounted to extend laterally in each direction respectively from the plates I5 and I6 inlet rings 20 and 2| are respectively mounted over the outer inlet ends of the blades. Each of these rings 20 and 2| is a planar metal disk having a central portion ,aremoved :to leave an gopening therethrough'having a diameter to position the inner edge of each ring to coincide with the point C of each of the blades so as to leave the inlet end of the blades l1 exposed, from that point Cito the point A within the opening of the ring. Likewise the inturned flanges about the openings 12 and I3 of the scroll terminate-toleavethe diameters of the openings [2 and i3 that of the opening diameters of the rings 20 and 2|. Any-suitablemeans maybe employed to rigidly secure the rings 20 and N .totthe inlet ,ends of the blades H, such .as byspot welding the ringsfto the ,flanges t9, the flat surfaces therebetween forminggood seats to prevent any twisting or skewing-action of the blades whenin operation at fairly highspeeds.

Another feature to be emphasized is that each blade I! has its inner edgelAadjacent the flange l8 flared or rounded back as .at-D,.Figs..2 and 3.

This slight change from thevstraight line edge aids considerably in .loading the blade for .its full length.

The central plates, l5 and [G and also theinlet rings 20 and.2l .extendradlally beyond the blades l l :for adistance. in the nature of flanges to per- .mit a full-volume of rair delivery against pressures higher than would otherwise be reached, permitting some velocity to be converted into pressure therebetween and within the scroll.

Back withinthe discharge opening ll of the scroll I is mounted anadjustable throat-member 22 comprising essentially a plate extending angularly inwardly and downwardly from the upper-transverse edge of the scroll opening and -turning around and toward the rings 20 and 2| flow of the air upon intake through the openings l2 and I3 is so directed-as to insure a full flow throughout the lengths-of the edges A whereby the-full capacities of the-blades I! are utilized all without any substantial interference by eddying of air at the inner ends of the blades and their inner edges. Obviously-a blower of a single set .of rotors. maybe employed, such as with plate lin theabsence-of plate It wheresmaller volumes are to be handled. Thesamegeneralefih:

ciency however is maintained within .thecapacity of the rotor,

While the. invention has been herein shown and described in more or less detail, it is obvious that structural variations may be employed, such as -in the mounting .of the blades :and in the construction of the scroll all without departing from the spirit'of the invention (the blades, however, being substantialiyconfined to the dimensions set forth), andII, therefore, do not desire to be limited to {that precise form beyond the l limitations as aybeimmsed by th liqllowin .claimsi ,I claim:

1. A blower rotor blade having ,a generally straight inner edge, the surface of the blade curving rearwardly from its inner edge by substantially a & unit radius to merge into a. major area of substantially 1% units radius, from which major area, the surface curves forwardly by substantially a .unit radius to the outer edge, the

distance between the inner and outer edges being substantially 1%, units.

2. In a blower, a rotor base plate; a plurality of blades mounted by ends circumferentially around the plate; each of the blades having an inner edge from which the forward surface curves rearwardly into a major area of flatter curvature, from which the surface curves around forwardly to the outer edge by a radius exceeding that of the surface, adjacent the inner edge; .and each ,of said blades being located around said plate to have its inner edge back ofa plate, radius lineacross the blade trailing edge; said surface adjacent the inner edge havingapproximatelya radius, the major area, approximatelya l% units radius, and the surface adjacent the outer edge, approximately a /2 unit radius.

'3. In a blower, a rotor base plate; aplurality of blades mounted by ends circumferentially around the plate; each of the blades having an inner edge from which the forward surface curves rearwardly into a major area of flatter curvature,,from which the surface curves around forwardly tothe outer edge by .aradius exceeding that of the surface adjacent the inner edge; and each of said blades being located around said plate to have its inner edge back ofa plate radius .line across the blade trailing edge; said surface adjacent the inner edge having approximately a e unit radius, the major area, approximately a 1% units radius, and the surface adjacentthe outer edge, approximately a unit radius; the spacing of the leading edge back of said radius line being approximately A; unit.

4. .In, a blower, a-rotor base plate; aplurality of blades mounted by ends .circinnferentially around-the plate; each of the blades having-an inner edge from which the forward surface curves rearwardly. into a major area of flatter curvature, from which the surface curves around forwardly to the outer edge by a radius exceeding that of the surface adjacent the inner edge; and each of said blades being located around said plate to have its inner edge back of a plate radius line :across the blade outer edge; and an inlet ring secured around and across the inlet ends of the blades, the inner edge of the ring being substantially on a circumferential line approximately centered across said blade major areas .to leave blade ends exposed through the ring.

,5. For a pressure type blower with a squirrel cage type rotor, a blade curved throughout its surface from its inner to its outer edge, both of said edges being substantially parallel to the axis of blade-revolutionand the elements in the blade surface being parallel throughout its width between said edges, said blade being further characterized by a major perceptibly curved area, from the inner side of which area the blade curves sharply forwardly to said inner blade edge bya radius of curvature less than that of said'major area, and from the outer side of which major area the blade curves forwardly to the outer blade edge by aradius of curvature less than that of said major area and greater than that'of said inner edge curved area.

VERNER E. SPROUS-E. 

